(Budget Travel) -- Pay one price and leave your wallet behind: It's an appealing concept. But how exactly does it work? And is it always worth it?

Does "all-inclusive" really mean everything is included? Are there charges I should watch out for?

There is no such thing as an entirely all-inclusive resort. And more importantly, each resort interprets the idea differently. Here's what you can count on wherever you go: Your rate will include your room and three meals per day (with well drinks). Beyond that, it simply depends on the place.

A basic -- but by no means universal -- rule of thumb is that activities located on the premises (tennis courts, game rooms, fitness centers) tend to be included, whereas those outside the resort (horseback riding, excursions to ruins) are generally not.

You'll usually also be charged for special services like babysitting and spa treatments. Resorts that specifically cater to families, such as Beaches, which touts its Sesame Street programs -- baking with Cookie Monster, story time with Elmo, that sort of thing -- throw in those activities with the base price. But Beaches' Character Breakfasts, in which families dine with Bert and Ernie, cost an extra $16 per child (under 16) and $12 per adult.

All that said, if you find yourself paying for extras, you're probably getting a better value. Why? Amenities are never really free; you're paying for them in the form of your room rate. The resorts that throw in every single activity are only worth the price if you're actually going to take advantage of most of the perks. In those cases, get ready to be busy with all the tennis lessons, sea kayaks, yoga classes, buffets, drinks....

You can expect it to be decent (and abundant). The big-name resorts pride themselves on offering a cruise-ship-like spectrum of options: Guests at a Sandals in the Bahamas, for example, have a choice of restaurants serving Italian, teppanyaki (Japanese), Bahamian, English pub fare, or Caribbean and Southwestern.

As for the three meals a day included in your rate, you usually have a choice of where to eat, but the number of choices varies widely -- from more than a dozen at mammoth resorts to as few as three at smaller properties. Some resorts also have restrictions about where and when you're allowed to eat. At the Barceló Ixtapa Beach hotel, for instance, guests can go to the waiter-serviced Spanish restaurant Don Quijote just once during a three-night stay. The rest of the time they're limited to the buffet or other casual spots.

What's the deal with tipping? I hate to stiff someone, but many all-inclusives say there's no tipping allowed.

The official policy at many resorts is that guests are discouraged from offering tips to employees for things like carrying your bags or serving you dinner. No one is supposed to be lingering at the door waiting for some cash, as they do in typical U.S. hotels. The unofficial policy: If you feel so inclined, go for it. There are certain scenarios in which tipping is definitely appropriate. If you're paying extra for an excursion or a spa treatment, the masseuse, driver, or guide should get 15 percent. Sandals resorts assign butlers to guests in high-end rooms, and the company recommends that you tip an average of $25 per day.

Should I bother joining any of the all-inclusive reward programs?

It can't hurt. Joining is usually easy and free, so why not? But don't expect rewards to be as generous as they are at traditional hotels. Free nights are especially hard to come by. With Club Med's Great Members reward program, introduced this past summer, it takes 50 nights to reach Silver status, at which point you're eligible for discounts of 10 percent off excursions and 15 percent off Club Med merchandise -- but no free rooms.

Riu's loyalty program, known as Riu Class, grants Gold card status if you've accumulated 1,600 points in two years -- at least 14 nights -- and gives rewards like late checkout or a choice of room assignment. Neither of these programs ever awards free stays. The Sandals Select program, on the other hand, does give you a chance to earn a seven-night vacation, but only after you've paid for 70 nights. If it's a free stay you truly want, you're better off earning points with a big hotel company that operates all-inclusives, such as InterContinental or Wyndham.

It seems like so many all-inclusive resorts are in the Caribbean and Mexico. Why can't I find any in other parts of the world?

The concept works best in destinations where guests want to stay put. You've paid for your meals and activities, so the way to get the most bang for your buck is to never leave the resort. If you're going to a place where you want to get out and explore -- a city loaded with markets, a medieval village with noted cobblestoned alleys, a seaside town lined with waterfront beach bars -- all-inclusive resorts are less appealing. (Can you imagine visiting Tokyo and eating in the same couple of restaurants the entire time?)

The bottom line: All-inclusives are most attractive in places where your primary goal is to veg out. That's why the experience can be so relaxing. It's all about what you're looking for.